universal-logs

universal-logs is a small npm package with two parts:

• A CLI that reads logs from HTTP endpoints or React Native Metro
• Runtime helpers that expose HTTP log snapshots from Node or Electron apps

CLI

Run against a named target from config:

npx universal-logs electron --limit 80

Run against an explicit endpoint:

npx universal-logs --endpoint http://127.0.0.1:6973/logs --limit 80

Read live React Native logs from Metro:

npx universal-logs metro --app com.fieldy --limit 80 --timeout 5000

List configured targets:

npx universal-logs list

Config

Create universal-logs.config.json in your repo:

{
  "targets": {
    "electron": {
      "endpoint": "http://127.0.0.1:6973/logs"
    },
    "api": {
      "endpoint": "http://127.0.0.1:6971/logs"
    },
    "native": {
      "provider": "metro",
      "metroUrl": "http://127.0.0.1:8081",
      "app": "com.fieldy",
      "timeoutMs": 5000
    }
  }
}

The CLI also reads package.json from a top-level universalLogs field.

Configured Metro targets work like any other target:

npx universal-logs native --limit 80

Metro is a live stream, not a snapshot. The CLI listens for new console events until it reaches --limit or --timeout.

Runtime

Expose a log buffer from a Node process:

import {
  createConsoleMirror,
  createLogBuffer,
  startHttpLogEndpoint,
} from "universal-logs/runtime"

const buffer = createLogBuffer({ limit: 500 })
createConsoleMirror({ buffer, source: "api" })

await startHttpLogEndpoint({
  buffer,
  port: 6971,
  service: "api",
})

Attach renderer logs in Electron:

import {
  attachElectronRendererConsoleMirror,
  createLogBuffer,
} from "universal-logs/runtime"

const buffer = createLogBuffer()
app.on("browser-window-created", (_event, window) => {
  attachElectronRendererConsoleMirror({
    buffer,
    webContents: window.webContents,
  })
})

Metro support does not need a runtime helper. It attaches to Metro's inspector endpoints at /json/list and /json, then listens for Runtime.consoleAPICalled over CDP.

Response shape

GET /logs?limit=100 returns:

{
  "service": "electron",
  "limit": 100,
  "total": 42,
  "entries": [
    {
      "timestamp": "2026-04-03T10:00:00.000Z",
      "level": "info",
      "source": "desktop:renderer",
      "message": "hello"
    }
  ]
}